| Environnement, ingénierie & développement |  |
Vol. 88 EID
1. Étude de la gestion actuelle des déchets urbains à Kinshasa par observation le long de l’avenue Université
The management of solid and liquid waste is one of the major challenges of the city of Kinshasa today. The question requires all the more attention as the sum of the constraints which continues to grow, weighs on the environment of the city. Sustainable waste management therefore requires a global reflection that takes into account all the problems, constraints and challenges of the space considered. Through the example of observations along University Avenue (Rond-point Ngaba to Boulevard Sendwe), we try to understand how to approach in an integrated way the problem of waste management along University Avenue (Sendwe Boulevard to Ngaba Roundabout). Systemic analysis seeks to highlight the disruptive effects of defective space management on the solid waste management system. Thanks to the elements of knowledge and response obtained, we propose a plan for waste management on University Avenue, Sendwe Boulevard section to Ngaba roundabout, based on the promotion of sanitation techniques and environmental education. Local residents. The aim is to tackle the problem as a whole with a systemic approach that situates waste management along University Avenue. This makes it possible to grasp the intrinsic and extrinsic dimensions of the causes and consequences of poor waste management
2. Variabilité spatiale de la qualité des eaux agricoles d’un bassin versant de deux arrondissements d’Antananarivo (Madagascar)
Context: Spatial analysis of water quality was carried out on agricultural area from lowland of watershed in Tana 2 and Tana 4 - Madagascar. Purpose: It aims to determine agricultural water quality and spatial distribution analysis of alkalinity, salinity and organic matter content. Methods: The agricultural zone was subdivided into three plots P1, P2 and P3 according to soil type. Water sample taken from 43 georeferenced points were intended for pH, Electrical Conductivity (CE) and Chemical Oxygen Demand (DCO) analysis. The spatial distribution was established by interpolating those indicator values using v.kriging from GRASS GIS software. Results and discussion: Water from P2 plot have high alkalinity. Those from P3 plots are very rich in dissolved salt and organic matter. The spatial distribution of alkalinity and salinity follows a linear model. While an exponential mode characterizes the distribution of organic contents
3. Méthode de quantification des flux des mines urbaines : cas des briques en terre cuite en Ile de France
The building sector is a large consumer of resources and a major producer of waste. In a context of resource depletion, the building sector will have to implement strategies to become more circular. One possible solution is to resort to urban mining, i.e., to see existing buildings as a resource pool available for future construction or renovation of the building stock during their deconstruction or renovation. This article proposes a method to compare the quantities generated by deconstruction and renovation to the needs of new construction or renovation projects. After deconstruction, building components may be suitable for various secondary uses from reuse to recycling. The uses issued from reuse and recycling are identified and the quantities of materials corresponding to each of them are determined with adequate units (m2, kg...) to be compared with the new buildings’ project’s needs. These units facilitate the comparison between the recovered materials and the demand of components and materials. The method assumes that circular economy is fully developed and that the focus is only on the technical feasibility of recovery methods, ignoring the socio-economic obstacles to reuse and recycling. To illustrate the method, the case of clay bricks in Ile-de-France is detailed. During the year 2020, 153 kt of clay bricks were produced by the demolition of buildings in this territory, allowing to obtain, for example, a maximum surface of more than 21,000 m2 of masonry bricks, […]
4. Potentiel des biochars à base de résidus agricoles pour le traitement des eaux usées domestiques par filtres à flux verticaux plantés d'Echinochloa pyramidalis
The treatment of domestic wastewater by vegetated filters is proposed as an alternative better suited to the socio-economic conditions of developing countries. The use of biochar in these filters in partial or total substitution of conventional filter substrate was the main aim of the present study. The effectiveness of three biochars produced from three crop wastes (Corn cobs, coconut shells and palm nut shells) in improving the purification performance of vertical flow filters vegetated with antelope grass was studied. The experimental set-up consisted of three biochar filters plus a control replicated thrice. The filters were supplied at a hydraulic loading rate of 142 l/m2/jr. The physi-co-chemical characteristics of the water were measured 30 and then 60 days from the beginning of the test; the physical growth parameters of randomly selected plants were measured weekly between the 30th and the 60th day, i.e. 4 times. The results reveal an increase in pH, an improvement in the reduction of nitrogen, iron, phosphorus, and microbes content effluents from biochar filters compared to those from conventional sand filters. Overall, the corn cob biochar filter showed better results after two months. It remains important for future studies to monitor the parameters over a longer period and to test the effect of the combination of the three biochars in one filter.